The present invention is related to power management and distribution (PMAD) systems and in particular to PMAD systems employing hybrid solid-state circuit breaker (SSCB) circuits.
Power management and distribution (PMAD) systems control the supply of DC and/or AC power to various loads. Circuit breakers and switches are commonly employed by these systems to not only control the supply of power to the various loads but also to protect the load from fault conditions. More recently, solid-state circuit breakers (SSCBs) have been employed to provide fast response time, eliminate arcing during turn-off, and prevent bouncing during turn-on transients. For example, power semiconductor devices such as metal-oxide semiconductor field effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBT) are commonly employed by SSCBs to control the distribution of power to a load. In particular, power MOSFETs are commonly employed due to their low conduction losses when conducting. The SSCB is part of a solid-state power controller (SSPC) that includes a controller, current and voltage sensors to monitor the current and voltage, respectively, provided to the load by a power semiconductor device and emulates traditional circuit breaker functionality by turning the power semiconductor device Off to protect the associated load from fault conditions. Thermal sensors may also be employed to protect the SSCB.
One of the specifics of SSCB is high overload requirements that may exceed 1000% of the rated current. To achieve this high current rating, a large number of MOSFET devices are connected in parallel. MOSFETS can be easily paralleled, because of the positive thermal coefficient of their on-state resistance. However, during overload transient conditions the MOSFETs within SSCB may be subject to a current imbalance that results in a particular device exceeding its peak current or continuous thermal ratings. This condition creates reliability concerns. Unbalance may be caused by parameter mismatches between semiconductor devices, gate drive parameter mismatches, and/or power circuit parameter mismatches. There is a need to improve SSCB and PMAD architecture to meet high overload transient requirements without over sizing the SSCB.